The proposed research will investigate the role of the frontal eye field (FEF) of the monkey in the control of eye movements to visual stimuli. It is usual to consider the FEF as an area that facilitates or produces eye movements to into contralateral visual space. Both the effect of electrical stimulation and the acute effects of damage to the FEF support this characterization. However, from research I have carried out on human brain-damaged patients, there is now reason to believe that frontal lobe mechanisms also aid in suppressing eye movements in certain circumstances, especially when a lateralized visual stimulus is irrelevant but visually attractive. I propose to test this conclusion by making unilateral FEF lesions in monkeys and studying their eye movements in conditions analogous to those in which the human subjects show evidence of hyper-reactivity to contralateral stimuli. The eye movements will be detected by means of a magnetic field technique which allows long-term and accurate recording without limiting the field of view. In a second stage, I shall attempt to determine which structures, presumably subcortical, appear to be disinhibited by FEF lesions and therefore produce inappropriate orienting responses to contralateral visual stimuli